China didn’t open “Pandora’s Sandbox.” It isn’t the first claimant to transform reefs by padding them with sand. But China’s superior economic and military capacity enables it to outpace other claimants. It is rapidly building the greatest “sandcastles,” which support multiple military and paramilitary functions. …

Considerable uncertainty over the ultimate extent to which China is altering the status quo makes it premature to liken South Sea island building to other historic Chinese geoengineering feats. The Great Wall and Grand Canal remain unequaled. But the real issue is Beijing’s relative capacity and lack of restraint in using it—restraint it demands of others’legal activities, such as U.S. missile defense. Overshadowing its neighbors makes prospects of further Chinese island augmentation and the potential announcement of a South China Sea ADIZ particularly troubling.